A surrogate used in air quality modelling can be generated from a surrogate weight shapefile, merging existing surrogates, or gapfilling a existing surrogate. Computer system scripts files with environment variables are often used to call srgcreate or srgmerge in the MIMS Allocator for generating surrogates.
A Java-based Surrogate Tool was developed to provide a more user-friendly way to use the Spatial Allocator. The Surrogate Tool uses user-defined text inputs to control which surrogates are generated, and the format of these files allows them to be easily edited and maintained in a spreadsheet program like Microsoft Excel. The merging and gapfilling programs were re-developed in Java with improved program design and implementation. There is no assumption in the new gapfilling tool. A Java summary report tool was also developed for quality assurance purpose. The tool summarizes all surrogates listed in a input file (SRGDESC.txt file) based on surrogate codes and counties. It gives reports about gapfilling, not sum to 1, or nodata information for each county of all surrogats. All java programs are packed into the SurrogateTools.jar file.
More information on the SurrogateTools is available at http://www.ie.unc.edu/cempd/projects/mims/spatial/srgtool/
To Section 4.2: Generating Surrogates from Weight Shapefiles